1. Field of the Invention
The present invention relates generally to a magnetic tape recording and/or reproducing apparatus (hereinafter referred to as a magnetic tape recording/reproducing apparatus) having a tape guide post mechanism, and more particularly, to a magnetic tape recording/reproducing apparatus having a tape guide post mechanism for preventing tilting of the tape guide post that extracts magnetic tape from a cassette loaded in a digital audio tape recorder (hereinafter xe2x80x9cDATxe2x80x9d) streamer used as a large-capacity external memory back-up device for computers.
2. Description of the Related Art
The DAT streamer uses a DAT tape cassette, with the magnetic tape being extracted from the DAT tape cassette via the tape guide post. Recording to and reproduction from the magnetic tape is carried out by a high-speed rotary drum, that is, a rotary head, the magnetic tape being driven between a capstan and a pinch roller and guided by a tape guide post. In order for the magnetic tape to run steadily the tape guide post must not be tilted. If the tape guide post is tilted, then unwanted force is generated in a direction of a width of the magnetic tape and, particularly when the tilt is great, the edges of the magnetic tape may be damaged and/or the tracking may slip, making it impossible to record and reproduce properly.
FIG. 1 and FIGS. 2A and 2B show a conventional tape guide post mechanism 10 of a supply reel side of a DAT streamer. As shown in the diagrams, the tape guide post mechanism 10 has a tape guide post arm 11, a tape guide post 12, a stopper 13, a pull arm 14, and the like. The arm 11 has a bearing part 11a on a base part side, a tape guide post 12 fixedly mounted on a forward edge side and a tube part 11b at a central part. The bearing part 11a is fitted to and rotatably supported by a pivot 16 provided on a chassis 15 not shown in the drawing. A pole 17 provided on an edge of the pull arm 14 is fitted to the tube part 11b from a lower side of the tube part 11b. 
After a DAT tape cassette 20 has been loaded, the pull arm 14 is moved in a direction indicated by arrow A in FIG. 2A, the arm 11 is pulled by the pole 17 and is rotated in a direction indicated by arrow B around the pivot 16. The tape guide post 12 extracts a magnetic tape 26 from the tape cassette 20. A forward edge side of the arm 11 presses against the stopper 13 and in that state determines the positioning of the tape guide post 12. The magnetic tape 26 is extracted from the supply reel side of the tape cassette body and is guided directly thereafter by the tape guide post 12.
As shown in FIG. 2B, the pole 17 exerts a force F1 on the arm 11 at a height position H1 and the stopper 13 exerts a force F2 on the arm 11 at a height position H2. Between height position H1 and height position H2 there is a difference in height C and, accordingly, a moment M is exerted on the arm 11 tilting so as to rotate with respect to an axis 18 in an extending direction of the arm 11. As a result, the arm 11 tilts and the tape guide post 12 tilts in a direction indicated by arrow D. The tilting of the tape guide post 12 is, however, restricted by the engagement of the bearing part 11a with the pivot 16. Normally, any gap between the side, and a tube part 70b at a central part as shown in FIGS. 6A and 7B. For ease of illustration, in FIGS. 6A, 6B, 6C and 6D, the tape guide post 71 has been simplified. The arm 70 fits the bearing part 70a to a cassette positioning mount 80 that is provided on the sub-chassis 47 so as to rotatably support the bearing part 70a by the cassette positioning mount 80. Further, the bearing part 70a is pushed upward in a Z1 direction by a spring 81.
If, however, for example, the gap between the bearing part 11a and the pivot 16 happens to be large, then the tilt of the tape guide post 12 becomes large as well, and can make the run of the magnetic tape unstable, generating unwanted force in a direction of a width of the magnetic tape and, on occasion, throwing off the tracking of the tape and interfering with proper recording and reproduction.
To counter this problem it is possible to increase the length of the pole 17 and thereby decrease the difference in height C described above. However, in doing so another problem arises, in that, when the pull arm 14 is pulled in the direction indicated by arrow A the pole 17 begins to tilt and a force exerted at the base of the pole 17 increases, with the possibility that the pull arm 14 deforms so as to twist. Accordingly, it is not desirable to increase the length of the pole 17.
Accordingly, it is an object of the present invention to provide an improved and useful magnetic tape recording/reproducing apparatus in which the disadvantages described above are eliminated.
Another and more specific object of the present invention is to provide a magnetic tape recording/reproducing apparatus that uses a cassette loaded in the apparatus to restrict the tilt of the tape guide post.
Another and more specific object of the present invention is to provide a magnetic tape recording/reproducing apparatus for recording information to and reproducing information from a magnetic tape extracted from a cassette loaded in the apparatus by the tape guide post that uses the loaded cassette to restrict the tilt of the tape guide post so that the tape guide post does not tilt when the tape guide post has reached a final position.
The above-described objects of the present invention are achieved by a magnetic tape recording/reproducing apparatus for recording information to and reproducing information from a magnetic tape extracted from a cassette loaded in the apparatus, the magnetic tape recording/reproducing apparatus having a tape guide post mechanism comprising:
a tape guide post provided on a rotatably supported tape guide post arm which rotates until pressing against a stopper, the tape guide post extracting a magnetic tape from the cassette loaded in the apparatus; and
a contacting part provided on a portion of the arm, the contacting part contacting a bottom surface of the loaded cassette when the arm is rotated so as to extract the magnetic tape from the cassette and the arm restricting a tilting of the arm in a direction in which the tape guide post tilts in a state in which the arm presses against the stopper.
According to the invention described above, by using the loaded cassette it is possible to effectively restrict the tape guide post so that the tape guide post does not tilt when the tape guide post has reached a final position.
Additionally, according to the invention described above, by contacting a top surface against the bottom surface of the loaded cassette, the arm restricts the tilting of the tape guide post, so the effect of variations in the quality of the fit between the arm bearing part and the pivot as described above can be eliminated and a tilt of the tape guide post can be prevented. That is, it is possible to restrict the tilt of the tape guide post even in the event that the fit between the arm bearing part and the pivot is poor, that is, the gap between the bearing part and the pivot is large.